The present invention relates to an assembly for a ball bearing with double raceway, and more particularly to an assembly for a ball bearing with double raceway which is preferably used in a pinion shaft such as a differential apparatus or the like, for example, mounted on a vehicle.
With reference to FIG. 22, a differential apparatus 60 disclosed in Japanese Unexamined Patent Publication No. 11-48805 is provided with a pinion shaft 63 within a differential case 61. The pinion shaft 63 has a pinion gear 62 engaging with a ring gear 77 of a differential speed change mechanism, in one side end portion in an axial direction.
The pinion shaft 63 is supported by tapered roller bearings 65 and 66 arranged apart in an axial direction so as to freely rotate around an axis. A companion flange 64 connected to a propeller shaft (not shown) is provided in an end portion of the pinion shaft 63.
The tapered roller bearing 65 is constituted by an outer ring member 69, and an inner ring side assembly in the outer ring member 69. The inner ring side assembly is constituted by an inner ring member 71, a plurality of tapered rollers 73 and a cage 75 holding the tapered rollers 73 at uniform positions in a circumferential direction.
The tapered roller bearing 66 is constituted by an outer ring member 70, and an inner ring side assembly in the outer ring member 70. The inner ring side assembly is constituted by an inner ring member 72, a plurality of tapered rollers 74 and a cage 76 holding the tapered rollers 74 at uniform positions in a circumferential direction.
A description follows of an assembling procedure of the differential apparatus 60, mainly with reference to a portion around the pinion shaft 63.
The outer ring members 69 and 70 are respectively pressure inserted against annular walls 67 and 68 of the differential case 61.
The inner ring side assembly constituted by the inner ring member 71, the tapered roller 73 and the cage 75 are assembled in such a manner that the inner ring member 71 is inserted into the pinion shaft 63.
The pinion shaft 63 in which the inner ring side member is assembled is assembled in the differential case 61 from one side of the differential case 61 in such a manner that the tapered roller 73 is brought into contact with a raceway surface of the outer ring member 69.
The inner ring side assembly constituted by the inner ring member 72, the tapered roller 74 and the cage 76 is assembled in the outer ring member 70 by inserting the inner ring side assembly into the pinion shaft 63 in such a manner that the tapered roller 74 is brought into contact with the raceway surface of the outer ring member 70.
A nut 75 is screwed with an outer end portion of the pinion shaft 63 close to the companion flange 64, and a predetermined pre-load is applied to the tapered roller bearings 65 and 66 by the pinion gear 62 and the companion flange 64.
In the differential apparatus 60, a large load is applied to the pinion shaft 63. Accordingly, a tapered roller bearing having a large load capacity is employed as a bearing for supporting the pinion shaft. The tapered roller bearing is of large load capacity, and on the other hand, has a large rolling resistance, thereby causing a reduction in efficiency of the differential apparatus 60.